Colorectal cancer (CRC) is the third most frequently diagnosed cancer and third leading cause of cancer death (after lung, prostate or breast cancer) in the United States. Importantly, unlike prostate, lung, and breast cancers, colorectal cancer screening may detect precancerous polyps or abnormal growth and prevent the development of CRC. With less than 40% of colorectal cancers are detected early, increasing CRC screening is important in all populations. In particular, understanding colorectal cancer screening practices is of great significance among individuals with mental illnesses, which at any given time constitutes approximately 20% of those eligible for colorectal cancer screening. There are barriers and interventions which might be specific to the population with mental illnesses, who are already more vulnerable to poor health outcomes and additionally, can be difficult to reach for treatment. Our preliminary secondary analysis of Veterans Health Administration data suggests that patients with mental illnesses have lower rates of annual fecal occult blood testing compared to an age and sex matched cohort of patients without mental illnesses. One size, one approach does not fit all. To be able to understand barriers and design appropriate interventions to improve colorectal cancer screening rates in this population, we need to first indentify screening rates and issues in various sub-groups of mental illnesses. This proposed secondary analysis study will provide us with that data and additionally, other provider and system related predictors for colorectal cancer screening in patients with mental illnesses. Our premise is that there are distinct barriers to CRC screening in sub-groups of mental illness and understanding those barriers will provide the foundation for effective intervention to improve life saving CRC screening rates. To conduct our analysis of colorectal cancer screening rates in individuals with and without the diagnosis of chronic mental illnesses, we will use a large veteran's health administration database which is the only national database with reliable measures of both primary care and psychiatric variables in one dataset. Results will provide a road map of screening disparities among individual sub-groups of mental illness. We will also identify the significance of demographic factors (such as age, sex, race) and system factors (such as having a primary care provider, frequency of visits to the primary care provider, participation in an integrated health care system involving a social worker and care coordinator) to colorectal cancer screening rates among various sub-groups of the mental illness population. We anticipate that this data will establish the array of barriers in this population and lay the groundwork for interventional studies to increase CRC screening rates among the mental illness population.